1. Field of the Invention
The present invention relates to a ride plate positioning mechanism for a personal watercraft, and to a method of using same. More particularly, the present invention relates to a ride plate positioning mechanism that provides for quick and accurate alignment of a ride plate with an opening portion provided in a bottom face of the watercraft's stem, and to a method of aligning a ride plate with an opening portion of a watercraft, using the described apparatus.
2. Description of the Background Art
A personal watercraft is known as a small size craft that is constructed and arranged to glide on the surface of a sea or lake. Many jet skis and other different types of personal watercraft are known and are commercially available. One example of a personal watercraft is described in Japanese Laid-Open Patent No. Hei 9-281132.
The personal watercraft described in this reference includes an engine and a jet propeller driven by the engine, both provided in a craft body, and also includes a steering nozzle at a rear end of the jet propeller. According to the personal watercraft, the jet propeller is driven by the engine to rotate an impeller of the water jet propeller, so that water is taken in through an inlet port of the craft bottom by the rotation of the impeller.
The water taken in is expelled rearwardly, as exhaust jet water from the rear end of the steering nozzle, so that the personal watercraft can be moved forward by the jetting force of the jet water.
A portion of the bottom face that forms the stern of the personal watercraft, below the water jet propeller, is formed by a ride plate, which is removable from the craft body. Since the ride plate is attached to the craft bottom, water can flow smoothly rearward along the ride plate.
Here, in order to reduce the resistance of the craft body against propulsion, and to allow the personal watercraft to glide favorably, it is necessary to accurately align and set the orientation of the ride plate, in the forward and rearward direction, on the craft body.
The ride plate is normally attached to the craft body by means of bolts, taking into consideration the ease of assembly to the craft body and the convenient disassembly for maintenance.
For example, the ride plate may be formed as a substantially rectangular plate, with attaching holes formed at four locations thereon, including left and right side portions of a front portion of the rectangular plate, and left and right side portions of a rear portion of the rectangular plate.
Meanwhile, threaded holes are formed at four locations on the bottom of the craft body, corresponding to the attaching holes of the ride plate.
In order to attach the ride plate to the craft bottom, the four attaching holes of the ride plate are aligned with the four threaded holes of the craft body. Then, bolts are inserted into the four attaching holes, and the bolts thus inserted are screwed into the threaded holes. Accordingly, the ride plate can be attached to the craft bottom of the craft body.
However, where bolts are used for fastening the ride plate, it is difficult to attach the ride plate to the craft body quickly and with a high degree of accuracy, due to an influence of the tolerance of the attaching holes or the bolts.
Particularly, it is difficult to assemble the ride plate to the craft body with a high degree of accuracy in regard to the orientation in the forward and backward direction. If it is tried to raise the accuracy in assembly, then more time is required for the assembly of the ride plate to the craft body, which makes an obstacle to improvement in the productivity.
Therefore, it is an object of the present invention to provide a ride plate positioning mechanism for a personal watercraft that can simply raise the alignment accuracy, in assembly, of a ride plate to a craft body.